Last reviewed: 20 Sep 2020
Last updated: 26 Aug 2020

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • dermatitis
  • insomnia, depression, or memory loss
  • intermittent stupor
  • hallucinations or delirium
  • weakness
  • peripheral neuropathy
  • oppositional hypertonus or myoclonus
  • cogwheel rigidity
  • primitive reflexes
  • ataxia
  • nausea, vomiting, or diarrhoea
  • glossitis, cheilitis, or stomatitis

Other diagnostic factors

  • fatigue
  • anxiety or paranoia
  • anorexia, weight loss, or cachexia
  • headache
  • vertigo
  • incontinence
  • constipation
  • heartburn
  • angular palpebritis

Risk factors

  • malnutrition
  • chronic alcohol use disorder
  • vitamin B2 (riboflavin) deficiency
  • vitamin B6 (pyridoxine) deficiency
  • malabsorption
  • eating disorders
  • Hartnup's disease
  • carcinoid syndrome
  • antituberculous drugs
  • Crohn's disease
  • HIV infection
  • copper deficiency
  • certain drugs
  • pregnancy and lactation
  • age >65 years
  • Alzheimer's dementia
  • Parkinson's disease

Diagnostic investigations

1st investigations to order

  • serum tryptophan
  • urinary N-methylnicotinamide
  • urinary N-methyl-2-pyridone-5-carboxamide
  • urinary 2-pyridone/N-methylnicotinamide ratio
  • skin biopsy
  • photosensitivity testing
  • FBC
  • serum albumin
  • serum protein
  • LFTs
  • gamma-GT
More 1st investigations to order

Investigations to consider

  • serum total iron
  • iron-binding capacity
  • ferritin
  • transketolase activity
  • thiamine pyrophosphate (TPP)
  • riboflavin coefficient
  • serum pyridoxal-5-phosphate
  • serum cyanocobalamin
  • serum folic acid
  • red cell folic acid
  • stool examination
  • neutral aminoaciduria
  • serum serotonin
  • platelet serotonin
  • urinary 5-hydroxyindoleacetic acid
  • HIV antibodies
  • mental-state examination
  • ECG
More investigations to consider

Treatment algorithm

Contributors

Senior Research Specialist

Centre for the Study of the Social and Environmental Determinants of Nutrition

Population Health, Health Systems and Innovation

HSRC

Cape Town

South Africa

Disclosures

WP declares that she has no competing interests.

Professor

School of Public Health

University of the Western Cape

Cape Town

South Africa

Disclosures

ZJM declares that she has no competing interests.

Professor Emeritus

Stellenbosch University

Professor Extraordinaire

University of Limpopo

South Africa

Disclosures

DL declares that he has no competing interests.

Dr Whadi-ah Parker, Dr Zandile J Mchiza, and Dr Demetre Labadarios would like to gratefully acknowledge Dr Nelia Patricia Steyn, a previous contributor, as well as Miss Nophiwe Job, Ms Nwabisa Tshefu, and Mr Machoene Derrick Sekgala for their contributions to this topic. NPS, NJ, NT, and MDS declare that they have no competing interests.

Peer reviewersVIEW ALL

Emeritus Professor of Clinical Chemistry

University of Liverpool

UK

Disclosures

AS declares that he has no competing interests.

CBNS

Queens College

City University of New York

NY

Disclosures

AM declares that he has no competing interests.

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